Today I started thinking about the grain-free pet food trend that is currently in vogue. First, I wondered how this craze evolved. I know it definitely did not originate in the professional veterinary community. I speculate that this movement was triggered in part by a pet food company's advertising campaign to generate a buzz around their unique pet food. I also suspect this pet food fad may be tied to the 2007 pet food contamination of wheat gluten with melamine, an industrial chemical used to make plastic. This tragic situation caused thousands of pets to become ill and many died of kidney failure. I believe pet food buyers felt betrayed by the big food companies and were actively looking for alternative diets.
What are grains? Grains are seeds of grasses cultivated for food, called cereals. The most common grains are wheat, rice, oats, corn, barley, millet, oatmeal, and quinoa. All grains are a good source of carbohydrates, which provide the body with energy. A grain seed is composed of a hard outer layer, called the bran, which is a good source of fiber. The inner portion, called the endosperm, provides a rich source of starch. The reproductive part of the seed is called the germ which has the potential to germinate into a new plant. The germ is a good source of micronutrients, like vitamin E, folic acid, magnesium and phosphorous. If the entire grain seed is used in food it is called whole grain. If it is processed, some of the nutritious elements may be lost and it will be labeled refined grain food.
Are all grains nutritionally created equal? No, grains vary in their nutritional composition and their health benefit is dependent on whether they have been processed or not. Some grains are higher in protein, like quinoa. Some grains are higher in fiber, like bulgur. Some grains have a higher content of anti-oxidizing agents, like yellow corn.
Should the average, healthy pet be on a grain-free diet? Not necessarily. Most dogs do great on dry pet foods that contain grains. In fact, some pets do better on diets with grains because of their high fiber content. When choosing a diet, I look for the Association of American Feed Control Official (AAFCO) seal of approval that tells me that the diet is nutritionally complete and balanced. In addition, I carefully read the ingredient list. I tend to gravitate to diets that have a single meat source with a few easily identifiable ingredients - it makes it easier later to identify and avoid ingredients should a pet experience diarrhea or have an adverse reaction. Whether a diet contains grains or not, is not a top criterion for me when it comes to selecting a diet for the average, healthy pet.
Can a pet be allergic to all grains? Absolutely not. Grains are antigentically distinct. It would be foolish to eliminate all grains from one's diet on the basis of an allergic reaction to one. Although it is unusual to be allergic to rice, it would not mean that the patient is also allergic to corn, or vice versa. The top three allergic provoking ingredients in cats are beef, dairy and fish. The top five allergic provoking ingredients in dogs, in descending order, are beef, dairy, wheat, chicken and egg.
Is it true that dogs are not designed to eat grains? No, dogs can digest grains. Your pet dog is not genetically equivalent to the ancient wolf that he arose from. The precise timing and location of this transformation is unknown but it is speculated to have occurred over tens of thousands of years ago. What is known, however, is that there are numerous genetic variations, or mutations, between the ancient wolf and our pet dog. In fact, to date, 10 key genes have been identified that demonstrate our domesticated dogs' increased ability to digest starch and fat relative to his ancient predecessor, the wolf. It is speculated that these mutations allowed the early ancestors of the modern dog to thrive on the discarded wheat and other crop products of early farmers and led to their domestication.
Will grains in my pet's dog food trigger mite allergies? A 2008 study, led by Spanish researcher and veterinarian Pilar Brazis, found two out of the 10 commercial dry dog foods studied by her group had storage mites. When the opened bags of food were stored for five weeks at 23 degrees Celsius and roughly 70 percent humidity (optimum environmental conditions for storage mite development), they discovered nine out of the 10 bags of dry dog food contained storage mites. Storage mites are a potential allergen for dogs. However, exposure to mites does not necessarily precipitate allergies. Very few pets suffer from mite allergies and therefore your healthy pet should not be harmed by the unintentional ingestion of a storage mite. To avoid this mite concern, however, I would recommend keeping pet food in a dry, cool environment and disposing of unused opened dry food every month.
Are genetically modified grains dangerous to my pet? Genetically modified grains are antigentically different from naturally occurring grains. One could speculate that by introducing a new ingredient into a pet's diet that it could potentially provoke an allergic response. However, have you ever tried a new ingredient and enjoyed the taste without any ill consequence?
Some argue that feeding genetically modified grains to our pets will create small fissures in the lining of the gastrointestinal resulting in the "leaky gut syndrome." Although not substantiated yet in the scientific community, it is feared by some that these fissures allow bacteria, toxins, incompletely digested proteins and fats to abnormally leak out of the intestine into the bloodstream. It is speculated that these elements, not normally found in the blood stream, trigger an autoimmune reaction resulting in bloating, gas, food sensitivities, fatigue, and skin rashes. This theory has not been proven and is truly speculative at this time.
If your pet is experiencing diarrhea, abdominal discomfort or having a skin problem, please consult your veterinarian for advice. Your veterinarian may suggest a unique protein food trial for eight to 12 weeks to see if food allergies or dietary intolerance is the reason your pet is not feeling well.
Do some pets benefit from a grain-free diet? Absolutely. Some dogs do benefit from grain-free diets but definitely not to the magnitude the pet food industry would lead you to believe. Some pets have allergies to specific grains and some pets have dietary intolerance to specific grains. There is no breed, sex, or age predilection. Pets with food allergies will usually display their symptoms by rubbing their face and ears, or by licking their paws or anus. Surprisingly, some pets with food allergies may have normal appearing stools. In contrast, pets with intestinal dietary intolerance do not normally process or absorb the ingredients in their pet food and frequently present with diarrhea. Most pets with food allergies or dietary intolerance have more than three bowel movements per day.
In conclusion, today I do not believe or support the grain-free pet food notion for all dogs. It is possible, however, in the future that a new piece of information may arise that may adjust my opinion. What I do know currently is that the regulation of the pet food industry and its advertising claims must improve. What we desperately need is more scientific research and non-biased analysis to make the best nutrition decisions for not only our pets but also ourselves.
Dr. Donna Solomon is a veterinarian at Animal Medical Center of Chicago and invites you to email her your questions or future topic ideas to doctors@animalmedicalcenterofchicago.com.